There's an extended version of the static pages plugin that lets you use PHP in static pages. You can download it from http://www.mediaaustralia.com.au/geek/public_html/
Alternatively, you could hack index.php and hard-code a block there that shows up just above the stories. A good place would be after the line that reads
$display .= COM_showMessage($HTTP_GET_VARS['msg']);
you can then just add
$display .= COM_startBlock ("My Block"
$display .= "Whatever you want";
$display .= COM_endBlock ();
(untested but should work)